Hi, I have been reading about the benefits of oil catch cans and always wondered why all cars do not come with them standard. The concept for direct injection engines makes total sense. Does anyone know if the M157 has some sort of oil separator so the PCV system does not vent the blow by fuel back to the air-intake? If not has any of you guys considered placing one? I have searched the forums and on the internet in general for these engines and almost no information about the CCV system. Any information would be greatly appreciated! Thanks in advance.

Regards,

LF

 

Mostly all PCV systems across all Makes aren’t going to have any kind of “catch” for the contaminants (oil/fuel/water) that are coincidingly being pulled into the intake tract with the vapors via vacuum.

I just did a search and found several threads asking about a catch can on the m157/m278. None of them have any posted solutions for whatever reason. Maybe people just don’t care to run them.

In my opinion, ALL direct injected cars should have one, particularly because they ALL run with a dirty intake tract, which slowly and eventually hurts efficiency and performance. Most cars have the engine bay space and they’re really not a hassle to drain when the oil’s being changed.

I do not have an e550 YET, but one of the first things I’ll be doing is sourcing a quality designed catch can and plumbing it in in place of the PCV system. They all work the same way (one exception below) and the only difference between catch cans is how well they filter out the contaminants from the air.

There are also catch cans that are ventilated and don’t use manifold vacuum to pull on the crankcase. These rely on PRESSURE inside the crankcase to push vapors and contaminants to the can. They’re better than nothing at all, but your car will smell like oil and fuel all the time, the cans are generally really cheaply made, and I believe in a number of states they’re illegal (don’t quote me on that). A sealed catch can utilizing vacuum is the way to go. They will do a better job of removing contaminants and pulling a vacuum on the crankcase technically reduces air friction, reducing parasitic hp loss..

Install a nice quality, sealed, and well filtered catch can setup, ideally with a quick drain valve on the bottom and a level indicator on the side, then consider doing a carbon cleaning and intake cleaning. Most of the oil will be in the intake, and depending on mileage, you may have build up on the intake valves. I’ve done a carbon cleaning on multiple cars now, and the most recent wasn’t even bad at all - but it still ran smoother and stronger after the cleaning. I can pretty much guarantee an intricate and powerful engine like these will be noticeably better.

Edit: I’d thought of using the car’s vacuum pump to do the pulling on the crankcase for the catch can. Like I’d mentioned, I don’t have the car yet, so I’ll have to take a look at that system and the pump itself to see if it’d be okay to run it on there. This would be the cleanest way to run the catch can. I may come back and report on this later when I get the car.